There are various manufacturing operations where it is required that 100% of the products produced thereby are weighed. Such weighing operations may be desired or required, for example, due to the high value of a particular product and/or for regulatory compliance.
Obviously, removing and individually weighing every product produced in a modern high-speed manufacturing operation is impractical. Therefore, devices for weighing products at high speed during a manufacturing or packaging operation have been developed and are known in the art. These devices include inline checkweighers where products to be weighed are passed over a weighpan while traveling along a conveyor or similar transport device. The products are appropriately spaced and the weighing components of the checkweigher are fast enough to allow the weight of each product passing over the weighpan to be detected.
Because such inline checkweighers weigh products while said products are in motion, the weight readings produced thereby are typically not as accurate as weight readings produced by static weighing devices. Consequently, the assignee of the present application has developed and markets an intermittent motion checkweigher that uses a rotating wheel to transport products to be weighed from an in-feed conveyor, across one or more weighing devices (e.g., load cells), to a discharge conveyor, where the products may be rejected or transferred downstream for further processing, packaging or shipping. The rotating wheel does not move the products continuously but, rather, moves with an indexing motion that allows a product (or row of products) to briefly rest over an associated weighing device. This allows a product to be weighed while the product is static. The products to be weighed by this intermittent motion checkweigher typically, but not necessarily, reside in some form of a container. One example of such a known intermittent motion checkweigher is illustrated in FIG. 1.
While this known intermittent motion checkweigher provides for highly accurate weighing, and has been commercially successful, its use is not entirely without drawbacks. For example, as can be observed in FIG. 1, the design of the known intermittent motion checkweigher makes use of an overhead mounted drive motor and product transport wheel. This overhead configuration inherently causes a loss of sight of a product when the product reaches the back side of the rotating wheel, and can complicate changing of the rotating wheel when such is required for processing products of different sizes or for cleaning purposes. Further, such an overhead configuration makes the integration and use of a filler device impractical, if not impossible. The known intermittent motion checkweigher is also designed to mount over an existing conveyor, meaning that the entire checkweigher must typically be lifted over the conveyor during installation. This installation technique and the fact that the in-feed and discharge locations of the rotating wheel are diametrically opposed typically also requires that the existing conveyor be cut in order to accommodate the checkweigher.
While the assignee's known intermittent motion checkweigher produces good results, it is nonetheless realized that improvements may be made thereto. Therefore, the present invention is directed to an intermittent motion checkweigher for providing highly accurate weight measurements of products of interest while overcoming at least the drawbacks described above.